Rate gyroscope



Aug. 16, 1949` H. KONET v 2,479,122

RATE GYROS COPE Filed Jan. 50, 1946 iiiisuiiummu TTTORN EY resented Aug.is, i949 RATE GYBOSCOPE Henry Konet, Paramus, N. J., assigner to BendixAviation Corporation, Teterboro, N. J., a oorporation of DelawareApplication January 3o, 194s. serial No. 644,379 I' s claims. (c1.745.s)

This invention relates to rate sensitive devices for aircraft or thelike and more particularly to a novel rate of turn gyro for indicatingthe rate of turn and/or generating a signal truly proportional to therate function developed by the craft or other vehicle or missilecarrying the gyro during a displacement about any one of its axes.

Rate sensitive devices of this character generally comprise a gyro rotormounted for spinning about one axis such as, for example, the craftstransverse axis, if the device is to respond to turn in azimuth, and forprocession about o. second axis perpendicular to the spin axis which, inthe example being considered, would be the crafts longitudinal axis. Aresilient constraint, usually in the nature of coil springs, cantileversprings, eddy-current damping devices, etc., is provided at theprecession axis to restrain gyro procession about the latter axis to anangie bearing a definite relation to the rate of turn of the craft.Where, in addition to an indication of the rate of turn, or in placethereof, it is desired to generate a signal proportional to the rate citurn for control purposes, and electrical pickoil' mechanism, generallyin the nature of a variable transformer is provided, one part of thepickoii being stationary and the other movable with the gyro rotor aboutthe axis of precession.

While suitable for most uses, rate sensitive devices of the knowncharacter have certain limitations making them undesirable forapplication Where rapid and extremely accurate responses are required.These limitations arise, ilrst of all. ben cause of the provision of thespring restraint which necessarily subjects the gyro rotor toundesirable oscillations, the natural frequency oi' which is low.Moreover, the presence of such springs develops the so-called cosineeffect which iniects another undesirable error into the gyro response bymaking it non-linear in character and requires the provision of specialscales in order to compensate for such non-linear responses. Further,provisions in the nature of dashpots have been relied upon to dampengyro rotor osciliations due to the springs and though effective to someextent another limitation was injected thereby, i. e., making the gyrosluggish in its response to small turns.

By the present invention, a novel rate of turn gyro is provided wherebythe restraining springs and dashpots are eliminated thereby permittingthte elimination of previously required bearings, hairsprings, etc., andthus overcoming all of the above limitations heretofore encountered withconventional devices of this character.

An obiect of the present invention, therefore, is to provide a novelrate sensitive device adapted for indicating the rate of turn and/orgenerating a signal truly proportional to the rate of turn for controlpurposes.

Another object of the invention is to provide a novel rate of turn gyrohaving a high natural frequency period thereby making it independent ofthe frequencies being measured.

A further object is to provide a novel raie of turn gyro wherein all thelimitations heretofore encountered with the use of similar gyros of theprior art have been overcome.

.Another object is to provide a novel rate of turn gyro whereinconventional restraining springs have been replaced with a novel andsubstantially rigid mechanism `which, during a turn, iimits the angulardisplacement oi the gyro rotor about its axis of precession to suc l adegree that the gyro remains substantially without motion and a systemis thereby provided having a high natural frequency making itindependent of the wide range of frequencies being encountered.

A further object is to provide a novel raie of turn gyro or rate signalgenerator in which the iull procession force of the rotor developedduring a turn is applied directly to a force sensitive device whereupona signal proportional to the precesslon force er torque is developed bythe latter device.

Another and farther obiect ci the present invention is to provide anovel rate of turn gyro wherein a substantially rigid precessionopposing member is provided which limits gyro precession or displacementto a negligible amount and associated with the rigid member is anelectric circuit so that upon the application of the precession torqueto the rigid member a signal is developed in the circuit trulyproportional to the rate of tum.

A further object is to provide a novel prece-ssion restraining memberfor a rate of turn gym in the nature of one or more electrical resistoror impedance elements whose resistance or impedance to current flowchanges with changes in the force applied thereon and arranged in anormally balanced electrical circuit to receive the full gyro precessiontorque to unbalance the circuit and develop therein a signal trulyproportional to the rate of turn.

The above and other objects and advantages o! the invention will appearmore fully hereinafter from a consideration of the detailed descriptionwhich follows, taken together with the accompanying drawing wherein oneembodiment of the invention is illustrated. It is to be expresslyunderstood, however, that the drawing is for the purpose of illustrationand description only and not designed as a definition oi' the limits ofthe invention.

In the drawings. wherein like reference characters refer to like partsin the several views,

Figure 1 is a top elevation view, with the top cover removed, of thenovel rate sensitive device of the present invention;

Figure 2 is a front end elevation view of the novel device of Figure 1with the novel precession restraining means thereof c Figure 3 is adetail view of the device of Figure 1; and

Figure 4 is a wiring diagram of the pick-ofi circuit utilized with thedevice of `Figure 1.

As' is well known to those skilled in the art of rate sensitivegyroscopes, the precession torque of such gyroscopes is given as T m owhere,

I mass of inertia of the gyro rotor,

n speed of turning about the chosen displacement axis, and,

o speed of gyro rotor rotation.

It is also well known, that theangle of gyro displacement during a turnabout a chosen axis due to the precession torque is D K T, where,

K spring constant, and, T gyro precession torque.

By 'the proper selection of the spring characteristic or constant K. theangle of displacement D may be readily predetermined. Obviously, themore resilient the spring the greater the oscillation of the system willbecome and its natural frequency period will be lower while theprovision of a substantially rigid precession opposing spring willsubstantially eliminate the oscillations of the system and increase thenatural frequency period to a value making it independent of the widerange of frequencies likely to be encountered for measuring and/orcontrol purposes.

The principle underlying the present invention, therefore, is to sorestrain the precession of a rate of turn gyro that its angulardisplacement during a turn will be substantially zero, such result beingachieved by the use of a substantially rigid member ior restraining oropposing gyro precession.

Referring now to the drawings for a more detailed description oi.' thenovel rate of turn device of the present invention, it is shown inFigure 3 as comprising a rotor III mounted for spinning about an axisII, the rotor being either electrically or pneumatically driven as iswell known in the art. Rotor. I0, further is provided with a rotorcasing I2 which is pivotally supvided in the form of a substantiallyrigid or nonelastic member whereby, during a turn. the gyro .motor ismaintained substantially Without motion about its axis of oscillationand to this end the front end of housing I4 is provided with a pair ofspaced and aligned slots I5 and I6, as shown in Figure 2, arranged aboveand below the pivotal point I3 of the rotor casing for accommodating theextended ends of a pair of bifurcated arms I1 and I8 which are attachedat their inner ends to rotor casing I2 by way of a plate support I9.

Secured to the front of housing I4 are pairs of spaced brackets 20, 2iand 2 2, 23, each being threadedto receive therein hollow threaded bolts24, 25, 26 and 2 1. Each pair of bolts 24, 25 and 26, 21 support thereinrods 28 and 29 formed of glass `or other suitable insulating material.the rods being spaced and parallel with each other and engaged at theircenters by arms I1 and I8, at their bifurcations, carried by the rotorcasing. Arranged on each rod 28 and 29 are carbon piles or stacks 30, 3land 3.2, 33, each pile or stack being formed of a series of carbon discsslipped on to the rod. Pile 3U, for example, is engaged at each of itsends by contact discs 34 and 35, disc 34 being engaged by a suitableinsulating disc 36 which is interposed between contact 34 and the freeend of bolt 24 while contact disc 35 is engaged by an insulating disc 31interposed between the latter contact disc and one side of arm I1, whilepile or stack 3i is engaged at each of its ends' by contact discs 38 and33, an insulating disc 40 being interposed between the opposite side ofarm I1 and contact disc 38 and a second insulating disc 4I beinginterposed between contact disc 89 and the free end of bolt 25. By ad=justing either bolt 2li or 25 or both the desired compression may beimpressed upon the carbon piles or stacks 3U and 3i.

Carbon piles or stacks 32 and 33 are arranged on rod 29 in generally thesame manner as are piles or stacks 30 and 3l, i. e., an insulating disc42 engages the free end of bolt 25 and a Contact disc 43 which, in turn,engages one end of pile 32, the opposite end of which is provided with acontact disc @i4 engaging an insulating disc 45 resting against one sideof arm i8, theopposite end of the arm being engaged by an insulatingdisc 4B which, in turn, engages one side of a contact disc 41 which isin contact with one side of pile 33, the opposite end of which engages acontact disc 48 resting against an insulating disc 49 which, in turn,rests against the free end of bolt '21. Adjustment of bolts 26 and 21performs 55 the same function as the operation of bolts 24 ported, asshown in Figure l, by way of studs I3 50 within an instrument vhousingI4 for oscillation about an axis perpendicular to the rotor spin axis.

As shown in Figure 1, by way oi' example only, the rotor spin axis II isshown as being normally vertical whereby the device so arranged would besensitive to the rate of displacement in climb or descent of the craftor missile carrying the device. If, on the other hand, it were desiredto measure the rate of displacement in azimuth, the gyro rotor will bemounted with its spin axis normally horizontal and parallel to thecrafts transverse axis and for oscillation about a second horizontalaxis perpendicular to the spin axis.

Novel precession opposing means are now proand 25.

As is known in the art, each of the carbon piles 3B, 3i, 32 and 33constitutes a force Asensing device in that each pile constitutes aresistor or impedance element whose resistance or impedance to currentiiow varies with the amount of force or torque impressed thereon. Forthis reason, the piles are arranged in a Wheatstone bridge circuit asshown in Figure 4. To this end, contact discs 35, 38 are electricallyconnected with eachother through a conductor 5U and a lead 5I to oneside of a suitable source (not shown) and contact discs 44, 41 areelectrically connected with each other through a conductor 52 and a lead53 to the opposite side of the source. The output of the circuit isconstituted by leads 54, 55 which connect with contact discs 34, 43 and39, 48, respectively.

Initially, bolts 24, 25, 26 and 21 are manipulated so that with arms I1and I8 on dead center of rods Il and 2l, i. e., with the rotor'spin axisIl normally vertical as shown in the example ot Figure i, the resistancevalues of the piles Ill, Il, l! and Il are made equal and the bridgecircuit is balanced so that no current ows at leads ll, Il. Assuming adisplacement about the axis o! oscillation, a precessing torque isdeveloped on thepart of the rotor tending to displace the rotor and itscasing angularly about the axis oi oscillation. The fact that arms I1,Il are in intimate contact through insulating discs l1, M and Ill, I8with piles 30, 3| and 32, 33 prevents the rotor and its casing fromangular motion about the 4axis of studs i3. However, the full torce ofprocession of the rotor is applied on piles 3h and 3S or piles 3| and32, depending upon the direction oi' gyro displacement, so that theirresistance to current flow is changed whereby the circuit is unbalancedand current ilows at output leads 54 and 55, this current being trulypropoi-tional to the rate of turn developed during the displacementbeing considered.

This current may be measured by a suitable electrical instrument 56connected to leads 54 and 55, as shown in Figure fi, the instrument being properly calibrated to give an indication oi leit or right turn. Onthe other hand, in addi" tion to or in place of measuring the currentdew veloped due to the application of the `full preses sion torque tothe related carbon piles, the ouinrl rent appearing across leads 54, 55may be fed into the input of a conventional vacuum tube amplifier 5l,the output of which energizes the variable phase 58 of a two phaseinduction motor 59, the second phase Ell of which may be constantlyenergized from a suitable source of current (not shown). The rotor oimotor 59 may be mechanically coupled with a control surface 6i so thatthe latter will be actuated in accordance with the rate signal developedby the novel rate generator hereof.

By providing a substantially rigid or non-elastic coupling, theoscillations previously occurring in rate of turn gyroscopes due to theuse of resilient @straining Springs have been eliminated and the naturalfrequency period of the system has been made high making it independentof the ire`1 quencies to be measured. Moreover, by the use of the novelprocession opposing expedient, a rate of turn gyro is provided which ismuch smaller and simpler than 'heretofore in that bearings, dash-pots,centralizing springs, hairsprings, etc., have lbeen eliminated.

Although but a single embodiment of the present invention has beenillustrated and described in detail, it is to be expressly understoodthat the invention is not limited thereto. Various changes can be madein the design and arrangement of parts without departing from the spiritand scope of the invention as will now be understood by those skilled inthe art. For example, carbon discs have been specied as constituting thepiles or resistors hereof for receiving the iull procession force of therotor, however, other suitable material may be used for this purpose inplace of carbon discs. For a definition of the limits of the invention,reference will be had primarily to the appended claims.

I claim:

1. In combination, a gyro rotor mounted for spinning about apredetermined axis, a frame supporting said rotor for oscillation abouta second axis resulting from a precession torque developed by said rotorin response tovan angular displacement of said rotor about said secondeil axis, a housing pivotally mounting said frame therein, meanscomprising a normally balanced bridge circuit including in two armsthereof spaced resistor elements whose resistances to current flowchange with the amount of force exerted thereon, a rod for supportingsaid resistor elements thereon arranged transversely of said secondaxis, means securing said rod to said housing, and means connected withsaid frame slidably engaging said rod intermediate said resistorelements i'or applying to one or the other of said elements theprocession torque developed by said rotor whereby said bridge circuit isunbalanced.

2. A rate signal generator comprising a gyro rotor mounted for spinningabout a predetermined axis, a frame supporting said rotor foroscillation about a. second axis resulting from a procession torquedeveloped by said rotor in response toan angular displacement of saidrotor about said second axis, a, housing pivotally supporting said frametherein, means comprising a normally balanced bridge circuit includingin all four arms thereof resistor elements whose resistances to currentflow change with the amount oi force exerted thereon, a supportingmember arranged transversely of and above said second axis forsupporting two of said resistor elements thereon in spaced relation toeach other, a second supporting member spaced from said first member andarranged transversely of and below Said second axis for supporting theremaining two of said resistor elements thereon in spaced relation toeach other, and means connected with said frame and slidably engagingboth of said supporting members intermediate both pairs of said resistorelements for applying to two of the resistor elements located above andbelow Said second axis the precession torque developed by said rotorwhereby said bridge circuit is unbalanced.

3. in combination, a gyro rotor mounted ior spinning about apredetermined axis, a frame supporting said rotor for oscillation abouta second axis resulting from a precession torque developed by said rotorin response to an angular displacement of said rotor about said secondaxis, a housing pivotally supporting said frame thereon, meanscomprising a normally balanced bridge circuit including in two armsthereof spaced hollow carbon pile resistors whose resistance to currentflow changes with the amount of force exerted thereon, means mountingsaid resistors thereon transversely of said second axis and fastened tosaid housing, and means conm nested with said frame slidably engagingsaid mounting means intermediate said resistors for applying to one orthe other of said resistors the procession torque developed by saidrotor whereby said bridge circuit is unbalanced.

4. In combination, a gyro rotor mounted for spinning about apredetermined axis, a frame supporting said rotor for oscillation abouta second axis resulting from a precession torque developed by. saidrotor in response to an angular displacement yof said rotor about saidsecond axis, a housing pivotally mounting said frame therein, meanscomprising a. normally balanced bridge circuit including in two armsthereof spaced hollow resistor elements whose resistances to currentilow change with the amount of force exerted thereon, a rod passingthrough said resistor elements and'arranged transversely oi said secondaxis, means mounting said md on said housing, and means connected withsaid trame `of said rotor, means slidably engaging said rod intermediatesaid resistor elements for applying to one or the other of said elementsthe precession torque developed by said rotor whereby said bridgecircuit is unbalanced.

5. A rate of turn gyro comprising a rotor mounted for spinning about apredetermined axis and for .irecession about a second axis perpendicularto said spin axis, means comprising a pair of spaced and axially alignedstacked hol- 10 low resistor elements for constraining precessionounting said elements transversely oi said sec d axis, and meansslidablyy engaging said mounting means intermediate lThe followingreferences are of ille of this patent:

UNITED STATES PATENTS Date Number Name 2,053,183 Crane et al. .v.. Sept.1, 1936` 2,137,974

Fischel Nov. 22, 1938 record in the *I

